1. Field of the Invention
This invention generally concerns gaming tokens such as disks, or flat plaques, or cards, integrating an electronic chip or an electronic identifier (called hereafter electronic identification device). The applications for the present invention are to be found, amongst others, in the contactless identification of persons and objects also called electronic labeling, and in the authentication, the identification and management (in particular the tracking and counting) of gaming tokens, also called casino chips. The expression “gaming token” covers any token that can be used in a gaming room and representing a value that is predetermined or not. Gaming tokens are usually made of a rigid plastic material to obtain a structure that is solid enough to resist conditions of use in casinos which are often very tough. The term “token” is used in this application to refer to any flat body that may include an electronic circuit.
2. Discussion of Background Information
U.S. Pat. No. 6,021,949, commonly owned with the present application, describes a gaming token or plaque, the body of which integrates an electronic chip and is made from laminated sheets of rolled plastic material. The electronic chip or electronic identifier includes an electronic circuit with a memory bearing identification and/or coding information concerning the person or object associated with the token (electronic label) or the token itself (gaming token or payment token), the electronic circuit generally being associated with an emitter-receiver connected to an antenna and adapted to be supplied by inductive coupling. The electronic chip is placed in the center of an opening provided in the body of the plaque, protected and held on either side by two rigid wafers and finally joined together and integrated into the body of the plaque by a lamination of top sheets of transparent cellulose acetate followed by the thermoforming of the assembly.
The manufacturing process for the body of the plaque incorporating the electronic chip by laminating thin sheets of plastic material described in the above mentioned patent was well adapted to highly decorated plaques and those representing a high nominal value, usually manufactured in small or medium sized series. However, a good protection of the electronic chip when it is integrated into the body of the plaque required a certain thickness (usually between 4 and 6 mm) so gaming tokens or plaques with a thickness of about 3 mm and equipped with an electronic chip were difficult to manufacture using this method with an excessive number of rejects resulting from the destruction of the chip.
To facilitate the manufacture of thinner game tokens, commonly assigned U.S. Pat. No. 6,581,747, the entire disclosure of which is hereby expressly incorporated by reference, discloses a gaming token or plaque or similar device made of plastic with a cavity in which an electronic identification device is placed. The electronic device includes an emitter-receiver and a peripheral antenna placed between two thin plastic films joined along their peripheries to form a protective envelope or pellet. The cavity offers at least one face opening closed by a plastic plug inserted into the cavity and assembled directly with the flat body, retaining the electronic device therein.
This structural arrangement made the token very robust while reducing its thickness by eliminating any superfluous layer of plastic. Furthermore, the simplification of their structure made the tokens much easier to manufacture. Plugs were inserted with a minimum clearance in the face openings of the cavities having matching shapes and directly assembled with the body of the token or plaque. The plug, inserted into the cavity in a solid state, possibly softened or pasty was deformed and welded to the body of the token by combined heating and pressure. Thus, the deformation capacity of the plug ensured a very robust weld, and a good cohesion between the token body and the thus completed electronic identifier.
However, the electronic device utilized in the above mentioned prior art, was of a relatively small physical size, incorporating components capable of operating with a relatively low frequency. To accommodate higher frequencies a larger size, typically a larger diameter, electronic pellet was necessary. The increased size was found to be accompanied by an increased incidence of breakage of the pellet envelope. Because the electronic pellet was heterogonous rather than homogeneous, stresses from the deforming plastic plug were concentrated at certain points of the envelope, causing the plastic film to break. Also, there was no direct interconnection between the upper and lower surfaces of the token, weakening the structure. Thus, the manufacturing process was accompanied by a high number of rejected defective tokens.